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From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Fred Isaman <iisaman@umich.edu>
Cc: Benny Halevy <bhalevy@panasas.com>,
	Fred Isaman <iisaman@netapp.com>,
	linux-nfs@vger.kernel.org
Subject: Re: [PATCH 07/10] pnfs-submit: avoid race handling return on close
Date: Tue, 15 Jun 2010 13:33:50 -0400	[thread overview]
Message-ID: <1276623230.8767.48.camel@heimdal.trondhjem.org> (raw)
In-Reply-To: <AANLkTilDj2Ua_t77kk5Gj_t0vqEcOJFKlqODAj18KQnm-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Tue, 2010-06-15 at 13:32 -0400, Fred Isaman wrote:
> On Tue, Jun 15, 2010 at 1:06 PM, Benny Halevy <bhalevy@panasas.com> wrote:
> > On Jun. 14, 2010, 21:46 -0400, Fred Isaman <iisaman@netapp.com> wrote:
> >> This prepares for the next patch.
> >>
> >> NOTE this doesn't really fix any current race, since
> >> layout going to NULL is OK.  But layout changing from NULL to nonNULL
> >> is a real race that is not fixed
> >>
> >> Signed-off-by: Fred Isaman <iisaman@netapp.com>
> >> ---
> >>  fs/nfs/nfs4state.c        |    5 +++--
> >>  fs/nfs/pnfs.c             |   11 +++++++++++
> >>  include/linux/nfs4_pnfs.h |    2 ++
> >>  3 files changed, 16 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> >> index d5144bd..8a7a64c 100644
> >> --- a/fs/nfs/nfs4state.c
> >> +++ b/fs/nfs/nfs4state.c
> >> @@ -594,11 +594,12 @@ static void __nfs4_close(struct path *path, struct nfs4_state *state,
> >>       } else {
> >>  #ifdef CONFIG_NFS_V4_1
> >>               struct nfs_inode *nfsi = NFS_I(state->inode);
> >> +             int roc = nfs4_roc_iomode(nfsi);
> >>
> >> -             if (has_layout(nfsi) && nfsi->layout.roc_iomode) {
> >> +             if (roc) {
> >>                       struct nfs4_pnfs_layout_segment range;
> >>
> >> -                     range.iomode = nfsi->layout.roc_iomode;
> >> +                     range.iomode = roc;
> >>                       range.offset = 0;
> >>                       range.length = NFS4_MAX_UINT64;
> >>                       pnfs_return_layout(state->inode, &range, NULL,
> >> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> >> index 6def09c..bd11ec7 100644
> >> --- a/fs/nfs/pnfs.c
> >> +++ b/fs/nfs/pnfs.c
> >> @@ -321,6 +321,17 @@ pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
> >>  #define BUG_ON_UNLOCKED_LO(lo) do {} while (0)
> >>  #endif /* CONFIG_SMP */
> >>
> >> +int nfs4_roc_iomode(struct nfs_inode *nfsi)
> >> +{
> >> +     int rv = 0;
> >> +
> >> +     spin_lock(&pnfs_spinlock);
> >
> > Why take the global lock rather than nfsi->lo_lock?
> >
> > Benny
> 
> You are right. That would be a copy-paste error.

What's an nfsi->lo_lock, and why do we need one?

Trond


  parent reply	other threads:[~2010-06-15 17:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-15  1:46 [PATCH 00/10] layout refcounting changes Fred Isaman
2010-06-15  1:46 ` [PATCH 01/10] pnfs-submit: separate locking from get and put of layout Fred Isaman
2010-06-15  1:46   ` [PATCH 02/10] pnfs-submit: split get_layout and grab_current_layout Fred Isaman
2010-06-15  1:46     ` [PATCH 03/10] pnfs-submit: remove list_empty check from put_layout Fred Isaman
2010-06-15  1:46       ` [PATCH 04/10] pnfs-submit: add backpointer to pnfs_layout_type Fred Isaman
2010-06-15  1:46         ` [PATCH 05/10] pnfs-submit: Move pnfs_layout_state and pnfs_layout_suspend back to nfs_inode Fred Isaman
2010-06-15  1:46           ` [PATCH 06/10] pnfs-submit: Add state flag for layoutcommit_needed Fred Isaman
2010-06-15  1:46             ` [PATCH 07/10] pnfs-submit: avoid race handling return on close Fred Isaman
2010-06-15  1:46               ` [PATCH 08/10] pnfs-submit: change nfsi->layout to a pointer Fred Isaman
2010-06-15  1:46                 ` [PATCH 09/10] pnfs-submit: API change: alloc_layout returns layout cache head Fred Isaman
2010-06-15  1:46                   ` [PATCH 10/10] pnfs-submit: filelayout: adjust to new alloc_layout API Fred Isaman
2010-06-15 17:06               ` [PATCH 07/10] pnfs-submit: avoid race handling return on close Benny Halevy
2010-06-15 17:32                 ` Fred Isaman
     [not found]                   ` <AANLkTilDj2Ua_t77kk5Gj_t0vqEcOJFKlqODAj18KQnm-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-15 17:33                     ` Trond Myklebust [this message]
     [not found]                       ` <1276623230.8767.48.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2010-06-15 17:52                         ` Fred Isaman
     [not found]                           ` <AANLkTimScICltrCrtEIz7qw1GzuaTGNwCVTk-ZTsZO4_-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-15 18:19                             ` Trond Myklebust
     [not found]                               ` <1276625991.2988.1.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2010-06-15 18:47                                 ` Benny Halevy
2010-06-15 17:00         ` [PATCH 04/10] pnfs-submit: add backpointer to pnfs_layout_type Benny Halevy
2010-06-15 16:56       ` [PATCH 03/10] pnfs-submit: remove list_empty check from put_layout Benny Halevy

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